@inproceedings{GouveiaHCSTPMR,
 author = {Gouveia, Luis and Leitner, Markus and Ljubi\'{c}, Ivana},
 title = {On the Hop Constrained Steiner Tree Problem with Multiple Root Nodes},
 booktitle = {Proceedings of the Second International Conference on Combinatorial Optimization},
 series = {ISCO'12},
 year = {2012},
 isbn = {978-3-642-32146-7},
 location = {Athens, Greece},
 pages = {201--212},
 numpages = {12},
 url = {http://dx.doi.org/10.1007/978-3-642-32147-4_19},
 doi = {10.1007/978-3-642-32147-4_19},
 acmid = {2368907},
 publisher = {Springer-Verlag},
 address = {Berlin, Heidelberg},
} 